A technology has conventionally been disclosed which improves the properties of a grain oriented electrical steel strip (hereinafter simply referred to as “steel strip” as appropriate) by printing an etch resist on a surface of the steel strip with an electrically insulating ink, and subsequently forming an etch pattern by an electrolytic etching process on the surface of the steel strip where the etch resist has been printed (refer to Patent Literature 1). An electrolytic etching process that is excellent in the stability of an etched state of a product has been requested to industrially perform such a technology for improving the properties of a steel strip using such an electrolytic etching process.
Patent Literature 2 proposes a method for obtaining the capability of uniform etching in a width direction of a steel strip by covering both sides of the steel strip and restraining the flow of an electrolyte in the width direction of the steel strip to obtain a uniform cross-sectional shape of a groove in the width direction.